Intua’s Beatmaker app for iPod Touch/iPhone
If you own an iPod Touch or an iPhone, and especially if you own one and enjoy making beats, I recommend this piece of sequencing software over anything else I’ve seen in the iTunes App Store.
It’s only version 1.02, but I’m already more than happy with it. WAV import/export, effects busses, bitcrusher, delay, eq, reverse, speed/pitch tuning, and even a waveform editor. I’ve been retiming breaks inside the machine very easily. Great for getting ideas down when you’re away from your music equipment, and even better for looking like a prick in cafés.
More information and video demos here